Add _bfd_elf_ifunc_get_synthetic_symtab

In i386 and x86-64 binaries with ifunc, relocations against .got.plt
section may not be in the same order as entries in PLT section.  This
patch adds _bfd_elf_ifunc_get_synthetic_symtab.  It takes a function
pointer which returns an array of PLT entry symbol values.  It calls
the function pointer to get the PLT entry symbol value array indexed
by relocation index, instead of calling plt_sym_val on each relocation
index.

	PR binutils/17677
	* elf-bfd.h (_bfd_elf_ifunc_get_synthetic_symtab): New prototype.
	* elf-ifunc.c (_bfd_elf_ifunc_get_synthetic_symtab): New
	function.
	* elf32-i386.c (elf_i386_plt_sym_val): Removed.
	(elf_backend_plt_sym_val): Likewise.
	(elf_i386_get_plt_sym_val): New.
	(elf_i386_get_synthetic_symtab): Likewise.
	(bfd_elf32_get_synthetic_symtab): Likewise.
	* elf64-x86-64.c (elf_x86_64_plt_sym_val): Removed.
	(elf_x86_64_plt_sym_val_offset_plt_bnd): Likewise.
	(elf_backend_plt_sym_val): Likewise.
	(elf_x86_64_get_plt_sym_val): New.
	(elf_x86_64_get_synthetic_symtab): Use
	_bfd_elf_ifunc_get_synthetic_symtab.
	(bfd_elf64_get_synthetic_symtab): Don't undefine for NaCl.

1 files changed, 71 insertions, 30 deletions

diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index dcf37b14a8..2bd7f43ade 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -5146,46 +5146,87 @@ elf_i386_finish_dynamic_sections (bfd *output_bfd,
   return TRUE;
 }
 
-/* Return address in section PLT for the Ith GOTPLT relocation, for
-   relocation REL or (bfd_vma) -1 if it should not be included.  */
+/* Return an array of PLT entry symbol values.  */
 
-static bfd_vma
-elf_i386_plt_sym_val (bfd_vma i, const asection *plt, const arelent *rel)
+static bfd_vma *
+elf_i386_get_plt_sym_val (bfd *abfd, asymbol **dynsyms, asection *plt,
+			  asection *relplt)
 {
-  bfd *abfd;
-  const struct elf_i386_backend_data *bed;
+  bfd_boolean (*slurp_relocs) (bfd *, asection *, asymbol **, bfd_boolean);
+  arelent *p;
+  long count, i;
+  bfd_vma *plt_sym_val;
   bfd_vma plt_offset;
+  bfd_byte *plt_contents;
+  const struct elf_i386_backend_data *bed
+    = get_elf_i386_backend_data (abfd);
+  Elf_Internal_Shdr *hdr;
+
+  /* Get the .plt section contents.  */
+  plt_contents = (bfd_byte *) bfd_malloc (plt->size);
+  if (plt_contents == NULL)
+    return NULL;
+  if (!bfd_get_section_contents (abfd, (asection *) plt,
+				 plt_contents, 0, plt->size))
+    {
+bad_return:
+      free (plt_contents);
+      return NULL;
+    }
 
-  /* Only match R_386_JUMP_SLOT and R_386_IRELATIVE.  */
-  if (rel->howto->type != R_386_JUMP_SLOT
-      && rel->howto->type != R_386_IRELATIVE)
-    return (bfd_vma) -1;
+  slurp_relocs = get_elf_backend_data (abfd)->s->slurp_reloc_table;
+  if (! (*slurp_relocs) (abfd, relplt, dynsyms, TRUE))
+    goto bad_return;
 
-  abfd = plt->owner;
-  bed = get_elf_i386_backend_data (abfd);
-  plt_offset = bed->plt->plt_entry_size;
+  hdr = &elf_section_data (relplt)->this_hdr;
+  count = relplt->size / hdr->sh_entsize;
+
+  plt_sym_val = (bfd_vma *) bfd_malloc (sizeof (bfd_vma) * count);
+  if (plt_sym_val == NULL)
+    goto bad_return;
 
-  if (elf_elfheader (abfd)->e_ident[EI_OSABI] != ELFOSABI_GNU)
-    return plt->vma + (i + 1) * plt_offset;
+  for (i = 0; i < count; i++, p++)
+    plt_sym_val[i] = -1;
 
-  while (plt_offset < plt->size)
+  plt_offset = bed->plt->plt_entry_size;
+  p = relplt->relocation;
+  for (i = 0; i < count; i++, p++)
     {
-      bfd_vma reloc_offset;
-      bfd_byte reloc_offset_raw[4];
-
-      if (!bfd_get_section_contents (abfd, (asection *) plt,
-				     reloc_offset_raw,
-				     plt_offset + bed->plt->plt_reloc_offset,
-				     sizeof (reloc_offset_raw)))
-	return (bfd_vma) -1;
-
-      reloc_offset = H_GET_32 (abfd, reloc_offset_raw);
-      if (reloc_offset == i * sizeof (Elf32_External_Rel))
-	return plt->vma + plt_offset;
+      long reloc_index;
+
+      if (p->howto->type != R_386_JUMP_SLOT
+	  && p->howto->type != R_386_IRELATIVE)
+	continue;
+
+      reloc_index = H_GET_32 (abfd, (plt_contents + plt_offset
+				     + bed->plt->plt_reloc_offset));
+      reloc_index /= sizeof (Elf32_External_Rel);
+      if (reloc_index >= count)
+	abort ();
+      plt_sym_val[reloc_index] = plt->vma + plt_offset;
       plt_offset += bed->plt->plt_entry_size;
     }
 
-  abort ();
+  free (plt_contents);
+
+  return plt_sym_val;
+}
+
+/* Similar to _bfd_elf_get_synthetic_symtab.  */
+
+static long
+elf_i386_get_synthetic_symtab (bfd *abfd,
+			       long symcount,
+			       asymbol **syms,
+			       long dynsymcount,
+			       asymbol **dynsyms,
+			       asymbol **ret)
+{
+  asection *plt = bfd_get_section_by_name (abfd, ".plt");
+  return _bfd_elf_ifunc_get_synthetic_symtab (abfd, symcount, syms,
+					      dynsymcount, dynsyms, ret,
+					      plt,
+					      elf_i386_get_plt_sym_val);
 }
 
 /* Return TRUE if symbol should be hashed in the `.gnu.hash' section.  */
@@ -5247,6 +5288,7 @@ elf_i386_add_symbol_hook (bfd * abfd,
 #define bfd_elf32_bfd_link_hash_table_create  elf_i386_link_hash_table_create
 #define bfd_elf32_bfd_reloc_type_lookup	      elf_i386_reloc_type_lookup
 #define bfd_elf32_bfd_reloc_name_lookup	      elf_i386_reloc_name_lookup
+#define bfd_elf32_get_synthetic_symtab	      elf_i386_get_synthetic_symtab
 
 #define elf_backend_adjust_dynamic_symbol     elf_i386_adjust_dynamic_symbol
 #define elf_backend_relocs_compatible	      _bfd_elf_relocs_compatible
@@ -5266,7 +5308,6 @@ elf_i386_add_symbol_hook (bfd * abfd,
 #define elf_backend_always_size_sections      elf_i386_always_size_sections
 #define elf_backend_omit_section_dynsym \
   ((bfd_boolean (*) (bfd *, struct bfd_link_info *, asection *)) bfd_true)
-#define elf_backend_plt_sym_val		      elf_i386_plt_sym_val
 #define elf_backend_hash_symbol		      elf_i386_hash_symbol
 #define elf_backend_add_symbol_hook           elf_i386_add_symbol_hook